BackgroundThe conditions for steam pretreatment of sugar cane bagasse and leaves were studied using CO2 as an impregnating agent. The following conditions were investigated: time (5 to 15 min) and temperature (190 to 220°C). The pretreatment was assessed in terms of glucose and xylose yields after enzymatic hydrolysis and inhibitor formation (furfural and hydroxymethylfurfural) in the pretreatment. Results from pretreatment using SO2 as impregnating agent was used as reference.ResultsFor sugar cane bagasse, the highest glucose yield (86.6% of theoretical) was obtained after pretreatment at 205°C for 15 min. For sugar cane leaves the highest glucose yield (97.2% of theoretical) was obtained after pretreatment at 220°C for 5 min. The reference pretreatment, using impregnation with SO2 and performed at 190°C for 5 min, resulted in an overall glucose yield of 79.7% and 91.9% for bagasse and leaves, respectively.ConclusionsComparable pretreatment performance was obtained with CO2 as compared to when SO2 is used, although higher temperature and pressure were needed. The results are encouraging as some characteristics of CO2 are very attractive, such as high availability, low cost, low toxicity, low corrosivity and low occupational risk.

Knowledge of the genetic variability of a population is essential to guide its preservation and maintenance in addition to increasing the efficiency of genetic breeding programs. On this basis, this study was conducted to evaluate the genetic diversity of Coffea canephora genotypes using multivariate statistical procedures applied to a set of morpho-agronomic variables. The materials employed in this study constitute a crop located in Vila Valério - ES, Brazil, where the genotypes are arranged in a randomized-blocks experimental design with four replicates. Significant differences were detected by the F test at the 1% or 5% probability levels among the genotypes for all evaluated traits, demonstrating heterogeneity of genetic constitution in the studied population, which is favorable to breeding, as it indicates the possibility to identify superior and divergent individuals. Based on the generalized Mahalanobis distance, the most divergent combinations were obtained between genotypes 23 and 10 (256.43) and 23 and 17 (250.09). The clusters formed by Tocher's optimization and the UPGMA hierarchical method agreed, both similarly grouping the genotypes into three clusters. Of the analyzed traits, mature fruit weight (19.08%), yield (15.50%), plant diameter (12.42%), and orthotropic-shoot internode length (10.94%) were the most efficient to explain the dissimilarity among the genotypes.

Objetivou-se avaliar a deposição de calda pulverizada e espectro de gotas no cafeeiro Conilon e as perdas proporcionadas com pulverizador hidropneumático, com e sem assistência eletrostática. O experimento foi instalado em delineamento de blocos ao acaso, com oito tratamentos (volumes de calda) e quatro repetições. Os volumes de calda com e sem assistência eletrostática, após diferirem em todas as características avaliadas no teste Skott-Knott, foram estudados separadamente. Para análise estatística da deposição, utilizou-se o esquema fatorial 4 (volumes de calda) x 2 (posições). Para análise do espectro de gotas, utilizou-se o esquema fatorial 4 (volumes de calda) x 3 (posições). Os volumes de calda pulverizados com a assistência eletrostática mostram resultados promissores para a tecnologia de aplicação dos produtos fitossanitários no cafeeiro Conilon, visto que a endoderiva foi reduzida em até 850%, a exoderiva em 323% e apresentou índices satisfatórios de cobertura e densidade de gotas.

In recent years, the expansion of sugarcane cultivation in Brazil and its growing importance in the Brazilian economy have been driven by a sharp increase in fuel alcohol production. This increase in fuel alcohol production was accompanied by increasing interest regarding the impacts of fuel crops in Brazil. In this study, regions of sugarcane expansion into deforested areas in the Atlantic Forest were studied by applying the emergy theory and indices. Environmental and economic inputs and the sustainability of the sugarcane production system were evaluated with the emergy method. The transformity (TR) was equal to 1.78E+11 seJ kg-1 , the yield rate (EYR) was equal to 1.30, the investment rate was equal to 3.29, the environmental load rate was equal to 4.33, the renewability rate was equal to 18.77, and the exchange rate was equal to 1.09. The emergy indices of corn, cassava, wheat, and sugarcane (as raw materials for ethanol production) were used. In Brazil, sugarcane production for ethanol production was more emergetically sustainable based on the analysed emergy indices.

Commercial substrates and their fertilization are essential for the morphophysiological, nutritional, and sanitary quality of seedlings. In this perspective, this study aimed to evaluate the quality of clonal seedlings of the black pepper cultivar Bragantina under doses of controlled-release fertilizers (CLF) in a commercial substrate. The treatments were constituted by five doses of the CLF Osmocote® 19-06-10 Mini Prill (3-4 months) (0, 2, 4, 6, and 8 kg m-3), with four replications of 16 cuttings. The CLF Osmocote®, especially in doses close to 4.16 kg m-3, showed to be promising for the production of clonal seedlings of the black pepper cultivar Bragantina.